Nobody is talking about this right now, but I actually think opinion of Pikachu has degraded to the point that he's being underrated. The idea of Pikachu being mid tier, to me, is ridiculous and unjustified.
There's a natural association between Esam and Pikachu, makes sense of course, but sometimes a clearer distinction needs to be made--I think Esam is personally struggling as a player right now and Pikachu is better than his recent results show.
Whenever I've watched Esam, I've noticed two things:
1) He almost always loses stocks because he does something stupid--recent examples from Pound would be totally random smash attacks that weren't close enough to the opponent to be read attempts, but rather trigger happy/misinput/not thinking through, missing QA cancels, and even screwing up his recovery and SDing.
2) He gets eliminated by Mario a frick ton. That's obvious, I think we all recognize that and realize Mario probably has an advantage over Pikachu, since he continuously loses to Marios and theory backs this up. However, when Esam gets eliminated by Marios early, opinion of Pikachu keeps dropping, and dropping... No other character gets as much slack for a single particularly bad MU as Pikachu does. This one poor MU and the effect it is having on Pikachu's results is creating an unjustly negative opinion of Pikachu to the point that he's being considered mid tier by some.
So then why do I think Pikachu is good, independent of Esam's poor showings---
1) His disadvantage is god like, and I think this is super important. QA is such a spectacular move for resetting--virtually impossible to entirely cover--that I think it singlehandedly puts him in a very good spot. QAs massive landing area combined with actual good falling aerials for landing (unlike most claims) in dair, or even side b for escaping to the ledge. This is in addition to a remarkable recovery, frame 3 nair and thunder for combo breaking, good ledge options, and his lack of being a fast faller, and size.
2) His neutral is really strong, this is generally accepted but sometimes ignored in discussion. Fair extends Pikachu a good distance and can contest a whole lot, retreating FH nair is fast, safe, and leaves Pika open for other defensive options if the opponent pursues, fsmash' range and safety (except when Esam randomly spams it), his dtilt has legitimately good range and sets up into stuff like more dtilts or grabs, dash attack is a killing burst option, and then the more obvious stuff like QA, SH dair (with FF/AC mixups), utilt, his speed, and I guess his projectile, and size (which does matter). Pikachu outright out neutrals the majority of the cast.
And we know about combos/edge guarding and all that.
Here's what I think Esam is doing wrong. He plays Pikachu's neutral unnecessarily risking and unsafely, when there is no reason to. Pika can wall with AC aerials and dtilt to stop approaches while simultaneously threatening his opponent because of QA's range. Esam just tries to force advantage state instead of playing out the neutral smartly,
Most importantly, Esam uses HORRIBLE options in disadvantage always. I so incredibly rarely see Esam QA out of pressure when it is one of the character's best aspects. He instead goes for random thunders, smash attacks, grabs, and non auto canceling dairs and fairs every time he gets put in disadvantage, and it doesn't ever pay off. I think as long as Esam shows he cannot play disadvantage (this was also painfully evident with his Corrin), he will continue to lose.
As for lack of kill setups, it's pretty true. But I also think that this community is overly focused on kill set ups. For instance, people say Bayo is obviously the best character right now, because of being all around good but with crazy kill confirms.
I actually think Sheik is the best character in the game, a character that thrives on neutral and disadvantage, while good in advantage, but lacks good kill confirms before weak nair to bouncing fish starts working.
In short, as long as Pikachu can easily tack damage while not dying himself, it can compensate for his killing problems. However, I am not saying Pikachu has as much trouble killing as Sheik, because I actually don't think he does with options like fsmash, falling fair confirms, random chance of getting uthrow thunder right, and in particular his usmash, though if all else fails uthrow and ftilt start killing. Also a better chance of gimping characters than most.
Esam has been having issues with inputs, continuously failing to rar thunder correctly (by which I mean he ends up missing Pika with the lightning), using the wrong moves during a combo at the wrong times and dropping opponents, and then the random move throwing habit, especially smash attacks. And when he whiffs a smash attack, he always charges it to the max instead of releasing early once he knows he's missed, which gives the opponent time to plan the optimal punish. Esam over the last year has gotten increasingly unsafe.
Don't get me wrong, Esam is a top 10 smash player, but I think specifically, recently, and not last year, he has been having personal play style issues. He needs to learn patience and optimize Pika's options better than he is. And he needs a secondary for Mario.
Anyways, I think Pika, especially after the last patch is definitely top 15 and should be top 10. And I think his MU spread is actually really good (but not as good as Esam thinks). he is not mid tier. I know like everyone will disagree but that's okay.